1. Field of the Invention
The present invention relates to a particle-removing apparatus for a semiconductor device manufacturing apparatus and to a method of removing particles, and more specifically it relates to a particle-removing apparatus that prevents the falling of particles that are generated during a process onto a wafer, and to a method for removing particles.
2. Description of the Related Art
Particles that are generated in the process of manufacturing a semiconductor device, and in particular in a process that makes use of plasma, are a cause of reduced yield and a deterioration of uptime. These particles can be caused by the peeling off of substances that have been deposited within the process equipment by reactions and by growth of substances generated by reaction within the plasma. To prevent the falling of these particles onto a substrate, as described in the Japanese Unexamined Patent Publications (KOKAI) No. 5-29272 and No. 7-58033, there has been a proposal of an apparatus in which the substrate is covered after a process is completed.
FIG. 9(a) is a drawing that shows a plasma etching apparatus of the past, in which the reference numeral 2100 denotes a processing chamber, inside which are provided an upper processing electrode 2200 and a lower processing electrode 2300, the upper processing electrode 2200 being grounded, and a high-frequency power supply 2400 being connected to the lower processing electrode 2300.
Above the lower processing electrode 2300 there is provided an electrostatic chuck electrode 2700, which is insulated by means of an insulator 1900, a voltage being applied to this electrostatic chuck electrode 2700 from a power supply 2600, so as to hold a semiconductor substrate 3000. The processing chamber 2100 is provided with an intake port 3100 for processing gas and an exhaust port 3200. A cover 3600 is provided so that particles do not fall onto the semiconductor substrate 3000.
FIG. 9(b) illustrates the general equipment operation cycle of a plasma etching process in a semiconductor device manufacturing process.
This process is for the case of a cycle in which a single substrate is processed. The substrate 3000, which is transported from a transporting port 3800, is transported to within the processing chamber 2100, at which point the process gas is introduced from the process gas intake port 3100. When the pressure within the processing chamber 2100 reaches a prescribed value, a high-frequency voltage is applied from the power supply 2400, so as to generated a plasma that etches the substrate 3000. Simultaneously with the above, the substrate 3000 is held by the electrostatic chuck. After completion of the etching, the supply of the high-frequency voltage, the supply of the process gas, and the electrostatic chuck are all stopped. After several seconds, an inert gas that does not contribute to etching is supplied for a prescribed amount of time in order to quickly purge the chamber of the process gas. The substrate 3000, after completion of this processing, is transported to outside the processing chamber 2100 from the transporting port 3800.
In an apparatus of the past as described above, in order to prevent particles from falling onto the substrate 3000, the cover 3600 is provided over the substrate 3000. According to an experiment by the inventor, however, in a semiconductor device manufacturing process that uses plasma, the timing of the falling of particles onto a substrate was shown to be intimately connected with the operating status of the semiconductor device manufacturing apparatus. Specifically, in the above-noted publications of the past, there was absolutely no consideration given to the timing of the covering of the substrate, this representing a major problem with regard to not being able to prevent the attachment of particles to the substrate.
Accordingly, it is an object of the present invention to improve over the above-noted drawback in the prior art, in particular by providing a novel particle-removing apparatus of a semiconductor device manufacturing apparatus and a method of removing particles whereby, by controlling the timing of the covering by a cover provided over the substrate in accordance with the processing condition of the substrate, the attachment of particles that are generated within the manufacturing apparatus during a process that uses plasma to the substrate is prevented.
It is another object of the present invention to provide novel particle-removing apparatus of a semiconductor device particle and method of removing particles whereby, by making use of the characteristic that particles are positively charged, attachment of the particles to the substrate is prevented without the use of a cover or the like.
In order to achieve the above-noted object, the present invention adopts the following basic technical constitution.
Specifically, a first aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in which a high-frequency voltage is applied between an upper electrode and a lower electrode so as to generate a plasma within a processing chamber that processes a substrate located in the processing chamber, in which is provided a cover that covers the substrate, the substrate being covered by closing this cover, so as to prevent the attachment of particles within the processing chamber to the substrate, this particle-removing apparatus being provided with a first control means for controlling the timing of the drive of the above-noted cover, this control means performing control so as to change the cover from the opened condition to the closed condition immediately before stopping the application of the high-frequency voltage.
In a second aspect of a particle-removing apparatus according to the present invention, control is performed so as to change the above-noted cover from the closed condition to the opened condition in synchronization with a tranport operation of a substrate-transporting apparatus that is provided in the semiconductor device manufacturing apparatus.
In a third aspect of a particle-removing apparatus according to the present invention, the timing of control of changing the cover from the closed condition to the opened condition is immediately before transporting the substrate after completion of processing to outside the processing chamber.
In a fourth aspect of a particle-removing apparatus according to the present invention, the timing of control of changing the cover from the closed condition to the opened condition is immediately after transporting the substrate after completion of processing to outside the processing chamber.
In a fifth aspect of a particle-removing apparatus according to the present invention, the timing of the control of changing the cover from the closed condition to the opened condition is immediately before the application of the high-frequency voltage.
In a sixth aspect of a particle-removing apparatus according to the present invention, in addition to imparting a potential to the above-noted cover, a second control means, for controlling the timing of application of the potential to the cover, is provided, this second control means performing control so that the potential is imparted to the cover minimally from immediately before the stopping of application of the high-frequency voltage to several seconds after the starting of introduction of a purging gas.
In a seventh aspect of a particle-removing apparatus according to the present invention, the above-noted potential is imparted minimally until immediately before the introduction of the purging gas.
In an eighth aspect of a particle-removing apparatus according to the present invention, the above-noted potential is imparted until the time at which the substrate is transported to outside the processing chamber.
In a ninth aspect of a particle-removing apparatus according to the present invention, the above-noted potential either is equivalent to a self-bias potential that appears on the lower electrode of the processing electrodes or has the same polarity as and a larger absolute value than the above-noted self-bias potential.
In a tenth aspect of a particle-removing apparatus according to the present invention, the above-noted potential is a potential that is equivalent to the potential on the lower electrode of the processing electrodes.
A first aspect of a particle-removing method according to the present invention is a particle-removing method in a semiconductor device manufacturing apparatus in which a high-frequency voltage is applied between an upper electrode and a lower electrode so as to generate a plasma within a processing chamber that processes a substrate located in the processing chamber, in which is provided a cover that covers the substrate, the substrate being covered by closing this cover, so as to prevent the attachment of particles within the processing chamber to the substrate, this particle-removing method performing control so as to change the cover from the opened condition to the closed condition immediately before stopping the application of the high-frequency voltage.
In a second aspect of a particle-removing method according to the present invention, control is performed so as to change the above-noted cover from the closed condition to the opened condition in synchronization with a transport operation of a substrate transport apparatus that is provided in the semiconductor device manufacturing apparatus.
A third aspect of a particle-removing method according to the present invention is a particle-removing method apparatus in a semiconductor device manufacturing apparatus in which a high-frequency voltage is applied between an upper electrode and a lower electrode so as to generate a plasma within a processing chamber that processes a substrate located in the processing chamber, in which is provided a cover that covers the substrate, the substrate being covered by closing this cover, so as to prevent the attachment of particles within the processing chamber to the substrate, this particle-removing method having a first step of changing the cover from the opened condition to the closed condition, a second step of stopping the application of the high-frequency voltage immediately after the cover is placed in the closed condition, and a third step of imparting a potential to the above-noted cover.
An eleventh aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma thereof, thereby processing the substrate on the above-noted susceptor, this particle-removing apparatus being provided with a particle-removing electrode for the purpose of removing particles inside the processing chamber, a negative voltage being applied to this particle-removing electrode, thereby causing removal of charged particles in the processing chamber.
In a twelfth aspect of a particle-removing apparatus according to the present invention, the above-noted particle-removing electrode is provided between the upper electrode and the lower electrode.
In a thirteenth aspect of a particle-removing apparatus according to the present invention, an exhaust port is provided on a side wall of the etching processing chamber in the region in which the particle-removing electrode is provided.
In a fourteenth aspect of a particle-removing apparatus according to the present invention, the particle-removing electrode is provided over the above-noted lower electrode, in a manner so as to surround the substrate.
In a fifteenth aspect of a particle-removing apparatus according to the present invention, the particle-removing electrode is provided between the processing electrodes and a processing chamber side wall.
In a sixteenth aspect of a particle-removing apparatus according to the present invention, the particle-removing electrode is an attachment-preventing plate that prevents attachment of sediments onto a wall surface of the processing chamber.
In a seventeenth aspect of a particle-removing apparatus according to the present invention, the particle-removing electrode is provided either within a gas intake or in the region of a gas exhaust port of the etching processing chamber.
An eighteenth aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, this particle-removing apparatus having a gas exhaust port of the processing chamber that is formed by an electrically conductive material, to which a negative voltage is applied so as to remove charged particles from within the processing chamber.
A nineteenth aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, this particle-removing apparatus being provided, between the upper electrode and the lower electrode, with an electrically conductive grid-configured material for the purpose of removing particles, a negative voltage being applied to the grid-configured material, so as to remove charged particles from within the processing chamber.
A twentieth aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, this particle-removing apparatus being provided, in the region of substrate, with a particle-removing electrode for the purpose of removing particles, a negative voltage having an absolute value that is greater than the self-bias voltage of the above-noted lower electrode being applied to this particle-removing electrode, so as to prevent the falling of particles within the processing chamber onto the substrate.
A twenty-first aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, a prescribed bias being added to the voltage that is applied to the lower electrode, this being varied in the same manner as the self-bias voltage, thereby causing charged particles to be directed toward the lower electrode, so as to prevent these particles from falling onto the above-noted substrate.
In a twenty-second aspect of a particle-removing apparatus according to the present invention, a laser apparatus is provided for the purpose of detecting the occurrence of the above-noted particles, light from this laser apparatus being shined in an area surrounding the above-noted upper electrode so as to detect the presence of particles inside the processing chamber, and a third control means being further provided for the purpose of applying a negative voltage to the particle-removing electrode, based on the results of this detection.
A twenth-third aspect of a particle-removing apparatus of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus in a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma thereof, thereby processing the substrate on the above-noted susceptor, this particle-removing apparatus being provided with a electrically conductive planar particle-removing electrode for the purpose of removing particles inside the processing chamber, a negative voltage being applied to this particle-removing electrode, thereby causing removal of charged particles in the processing chamber.
In a twenty-fourth aspect of a particle-removing apparatus according to the present invention, the above-noted particle-removing electrode is in the form of a grid-configured electrically conductive electrode.
In a twenty-fifth aspect of a particle-removing apparatus according to the present invention, the above-noted negative voltage is applied after the completion of etching.
In a twenty-sixth aspect of a particle-removing apparatus according to the present invention, the above-noted negative voltage is applied during transport of the substrate.
A fourth aspect of a particle-removing method of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing method for a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber, a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, and a particle-removing electrode for the purpose of removing particles being provided inside the processing chamber, whereby, after completion of the etching of the substrate, a negative voltage is applied to the particle-removing electrode, so that charged particles inside the processing chamber are guided to this particle-removing electrode and caused to be attached to the particle-removing electrode, thereby preventing the particles from becoming attached to the substrate.
In a fifth aspect of a particle-removing method according to the present invention, after the application of the negative voltage to the particle-removing electrode, the etching gas in the processing chamber is exhausted.
A sixth aspect of a particle-removing method of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing method for a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber, and a prescribed voltage o being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, wherein a gas exhaust port of the processing chamber is formed of an electrically conductive material, and a negative voltage is applied to this exhaust port, so as to guide charged particles toward the gas exhaust port and simultaneously exhaust the etching gas from within the processing chamber.
An seventh aspect of a particle-removing method of a semiconductor device manufacturing apparatus according to the present invention is a particle-removing method for a semiconductor device manufacturing apparatus that has an etching processing chamber, a pair of processing electrodes formed by an upper electrode and a lower electrode, which are installed within the processing chamber, and a susceptor that holds a substrate to be processed onto the top of the above-noted lower electrode, a processing gas being introduced into the etching processing chamber, and a prescribed voltage being applied to the above-noted processing electrodes, so as to generate a plasma of the gas, thereby processing the substrate on the susceptor, wherein by causing the size of the generated plasma to greatly extend beyond the substrate, particles inside the processing chamber are caused to fall along the periphery of the plasma, so that they are prevented from becoming attached to the substrate.
A particle-removing apparatus for a semiconductor device manufacturing apparatus according to the present invention is a particle-removing apparatus for a semiconductor device manufacturing apparatus in which a high-frequency voltage is applied between an upper electrode and a lower electrode to cause a plasma within the processing chamber so as to process a substrate therewithin, a cover that covers the substrate being provided, the substrate being covered by changing cover to the closed condition, so as to prevent particles within the processing chamber from becoming attached to the substrate, and a first control means that controls the timing of the drive timing of the cover being also provided, this first control means performing control so that the cover is changed from the opened condition to the closed condition immediately before stopping the application of the above-noted high-frequency voltage applied between an upper electrode and a lower electrode, and so that the cover is changed from the closed condition to the opened condition in synchronization with a transporting operation of a substrate transport apparatus provided in the semiconductor device manufacturing apparatus.
Therefore, by driving the cover so as to cover the substrate immediately before particles are generated, the attachment of the particles to the substrate is prevented.
Additionally, by imparting an appropriate potential to the cover, the cover has a dust-collecting action, enabling even more effective prevention of attachment of the particles to the substrate.
Next, yet another aspect of an embodiment of the present invention will be described.
FIG. 21 is a photograph of the behavior of particles in a plasma, inserted into a schematic representation of the apparatus. The right edge of the drawing corresponds to the region at the center of the process apparatus, and the left edge corresponds to the region of the wall of the process apparatus.
Particles are trapped in a sheath region in proximity to the upper electrode as shown in FIG. 21 and, at the instant the plasma collapses, so that the particles in the region of the upper electrode fly toward the outer walls by the potential of the afterglow plasma. In the center part of the chamber, however, the particles fall downward around the outside of the plasma, and in the region of the lower electrode, this being the region of the wafer, it can be seen that the negative self-bias potential causes the particles to fly towards the wafer.
From the above-noted results, the particles are seen to be positively charged, and the basis of the present invention is the use of this fact to remove the particles using electrostatic induction.
FIG. 9(b) shows an example of the relationship between the number of particles that are generated in the etching apparatus during operation, and the operation condition of the apparatus at that time.
The apparatus that is shown in FIG. 9(a) is an etching apparatus of the past that has flat parallel processing electrodes.
FIG. 9(b) is a representation of a cycle of processing one substrate. When the substrate is transported to inside the processing chamber from the transporting port, the processing gas is supplied and, when the pressure within the processing chamber reaches a prescribed value, a high-frequency voltage is applied, so as to generate a plasma, thereby causing etching of the substrate. When this is done, the substrate is held by the susceptor on the top of the lower electrode.
After completion of the above-noted etching, the supply of the high-frequency voltage, the supply of the process gas, and the electrostatic chucking are all stopped. After several seconds, an inert gas that does not contribute to etching is supplied for a prescribed amount of time in order to quickly purge the chamber of the process gas, this causing the pressure within the processing chamber to rise.
The substrate, after completion of this processing, is transported to outside the processing chamber from the transporting port. In the drawing, the number of particles P represented by the ellipses is the result of introducing the light from a laser into the region over the substrate in the processing chamber, and using a CCD camera to photograph the light scattered by particles that traverse this laser light, a signal that indicates the operating condition of the etching apparatus being simultaneously captured. The number shown is the accumulated number obtained from the processing of 25 substrates.
From FIG. 9(b), it is clear that the occurrence of particles P during etching corresponds to the operating condition of the apparatus. That is, while there is almost no particle generation during etching, when the etching is completed, there is a time when a large number of particles are generated, and the frequency of generation of particles is high when the purging gas is introduced.
A detailed examination of the images obtained from the light scattered by the particles revealed that the traces of particles at the time of the completion of the etching exhibit a tendency to be directed toward the substrate, and a tendency to be directed toward the exhaust port when the purging gas is introduced.
From the above, it can be envisioned that because the high-frequency power supply is stopped when the etching is completed, particles that float during etching fall and, because the viscous flow of the processing gas is small, the particles fly toward the substrate, on which all of its electrical charge have not been removed.
It is further envisioned, however, that several seconds after the completion of etching, purging gas is introduced, the result being that the particles head toward the exhaust port with the purging gas.
In the present invention, the wafer is covered when the supply of voltage is stopped. Also, using the fact that the particles in the processing chamber are positively charged, by imparting a negative potential to an electrically conductive plate or grid, the generated particles are trapped, or caused to migrate toward the exhaust port, thereby preventing them from reaching the substrate.